Wednesday, July 23, 2014

New excuse for the 'pause': Negative phase of the natural Interdecadal Pacific Oscillation

Matthew "say anything" England is back with a new paper which offers yet another excuse for the 17+ year pause in global warming: the negative phase of the natural Interdecadal Pacific Oscillation (IPO) [excuse #14 by my count].

"We further demonstrate that most non-volcanic hiatuses across CMIP5 models are associated with enhanced cooling in the equatorial Pacific linked to the transition to a negative [Interdecadal Pacific Oscillation] IPO phase."

"...they can’t ignore our arguments any longer. For many years we had been hearing from the “scientific consensus” side that natural climate change is nowhere near as strong as human-caused warming…yet the lack of surface warming in 17 years has forced those same scientists to now invoke natural climate change to supposedly cancel out the expected human-caused warming!

C’mon guys. You can’t have it both ways! They fail to see that a climate system capable of cancelling out warming with natural cooling is also capable of causing natural warming in the first place."

The latest generation of climate model simulations are used to investigate the occurrence of hiatus periods in global surface air temperature in the past and under two future warming scenarios. Hiatus periods are identified in three categories, (i) those due to volcanic eruptions, (ii) those associated with negative phases of the Interdecadal Pacific Oscillation (IPO) and (iii) those affected by anthropogenically released aerosols in the mid 20th Century. The likelihood of future hiatus periods is found to be sensitive to the rate of change of anthropogenic forcing. Under high rates of greenhouse gas emissions there is little chance of a hiatus decade occurring beyond 2030, even in the event of a large volcanic eruption. We further demonstrate that most non-volcanic hiatuses across CMIP5 models are associated with enhanced cooling in the equatorial Pacific linked to the transition to a negative IPO phase.